I am using the SciChart API for 2D Charts from SciCharts, I wanted to know if it is possible to know the min and max visible index/indices from ISCIAxisCore.
I need to get this information from the callback made to SCIVisibleRangeChangeListener when visible range as changed. So I can calculate some extended information, all the data is stored in a few arrays and the graph is only showing a section of it and I need to show some average values based on the visible range of the graph.
I know I could use Swift API to get the index out of the array but this seems to me like the most inefficient way of getting the visible min and max index of the data set, as it will need to search in a data set that can span more than 5k records.
I suspect, you are looking for one of the following:
search index range directly on the DataSeries, using -getIndicesXRange:xCoordinateCalculator:
search index in the underlying ISCIList, via the -findIndexOf:searchMode:isSorted: on the dataSeries.xValues
I added the following listener with prints into our Line Chart Example, which showcases how to use getIndicesXRange:
xAxis.visibleRangeChangeListener = { (axis, oldRange, newRange, animated) in
guard animated == false else { return }
if let axis = axis, let min = newRange?.minAsDouble, let max = newRange?.maxAsDouble {
let indicesRange = SCIIndexRange()
dataSeries.getIndicesXRange(indicesRange, xCoordinateCalculator: axis.currentCoordinateCalculator)
print("Values: \(min) : \(max)")
print("Min: \(indicesRange.min), Max \(indicesRange.max)")
}
}
Hope that helps.
Related
In widget iOS14, I want to show values in graphical form using bar chart.
I have used this library "https://github.com/dawigr/BarChart" to draw bar chart.
But in Xcode12+, it's not showing negative values and considering negative value as 0 and throwing warning as shown in screen shot.
"[SwiftUI] Invalid frame dimension (negative or non-finite)"
You could try to normalise your input Values to prevent getting errors like this.
e.g.: if your data set contains values from -10 to 100, your min normalised value would be 0 and your max normalised value 1. This only works if your numbers are CGFloat, Double or something like this, numbers in Int format would be rounded up.
This could be done by using an extension like this:
extension Array where Element == Double {
var noramlized: [Double] {
if let min = self.min(), let max = self.max() {
return self.map{ ($0 - min) / (max - min) }
}
return []
}
}
I don't no how you get your values for the frame exactly, but I think you did something like this:
// normalise your data set:
let data : [Double] = [Double]()
youChart(inputData: data.noramlized)
// get values for the frame
let height = data.noramlized.max()
// if your normalised value is too small for your purpose (your max will always be 1.0 but in relation to the rest it might fit), you can scale it up like height * 20.
// the width might be a non changing value that you will enter manually or it will append on the count of bars in your chart.
Is it possible to set the chart zoom to a range of values within the dataset? So currently we have a chart that can display close to 100 values within it. What we're trying to achieve is the ability to zoom into a range of values i.e. The first 12 values within the dataset and then the user is able to scroll in either direction to see the remaining values within the chart.
We've currently tried using the setVisibleXRangeMaximum function but that only seems to display the first value within the chart rather than 12. And this may be because the data that we receive from he service can be unpredictable i.e. one value may be 1000 and the next maybe 100,000.
This is an extension that will let you zoom into a range of values like this:
extension BarLineChartViewBase {
func focusXRange(start: Double, end: Double) {
guard end > start else {
return
}
// Reset the zoom back to the full chart view, so that the setVisibleXRange call will zoom in to the desired range,
// setVisibleXRange only zooms in, not out.
// resetZoom() seems like it should be the right API call, but it doesn't work if the user is already zoomed
// in closer than the range to focus.
// zoomToCenter(scaleX: 1, scaleY: 1) similarly doesn't work
while !isFullyZoomedOut {
zoomOut()
}
let distance = end - start
// If the distance to focus on is greater than the xAxis maximum, we can't zoom in any further
guard distance < (xAxis.axisMaximum - xAxis.axisMinimum) else {
return
}
// Set the visible range to the distance between start and end. This will zoom the chart in to a range of that distance
setVisibleXRange(minXRange: xAxis.axisMinimum, maxXRange: xAxis.axisMinimum + distance)
// Move the chart to the start point
moveViewToX(start)
// Due to the previous setVisibleXRange call, the user cannot zoom back out.
// Restore the visible range to the full width of the dataset, so that the user can zoom back out.
// Note: this will not zoom the chart back out; setVisibleXRange will only zoom in, not out
setVisibleXRange(minXRange: xAxis.axisMinimum, maxXRange: xAxis.axisMaximum)
}
}
// Use it like
// chartView.focusXRange(0, 10) // Focus on the first ten data points
// chartView.focusXRange(chartView.xAxis.axisMaximum - 10, chartView.xAxis.axisMaximum) // Focus on the last ten data points
OK, my final issue with getting my bar chart setup is how to print the X axis labels. I tried this:
if let axis = graph.axisSet as? CPTXYAxisSet, xAxis = axis.xAxis {
let dateLabels = self!.dates!.map {
CPTAxisLabel(text: NSDateFormatter.localizedStringFromDate($0, dateStyle: .ShortStyle, timeStyle: .NoStyle), textStyle: nil)
}
xAxis.axisLabels = Set(dateLabels)
}
I'm getting nothing displayed though. I looked at DatePlot sample but I don't want to do what it's doing as it incorrectly assumes that a day is 86,400 seconds long, and that will break multiple times. Also, my date offsets are in months, so that makes it even worse. Can't I just somehow provide the already formatted date string?
Seems strange to me that "axisLabels" would be a set, since a set is not ordered.
Each axis label has a tickLocation. Set the tick location to the bar location for that label in the same units used in the plot space and datasource. Since the label tick location is not related to its position in the array, we can use an unordered collection like a set.
I have a requirement where i have to show custom points on x-axis instead of dates values. Also same custom data points needs to be shown on navigator as well. In the below Js fiddle, i am converting data (Per13/2016 etc) into equivalent date values and then binding the chart using converted date values.
Below is the link of the JS fiddle:- Fiddle link
In the Js fiddle, i am showing Per1,Per2 etc.on x-axis and same has to be shown on navigator as well.
Now i am facing problem with the navigator,when i changes the range using slider ,the x-axis labels changes but not according to the range selected.Also tool-tip formatting is getting changed.
Can you please let me know how to handle this scenario and best way to do the same.
//few code lines to post fiddle link
xAxis: {
labels: {
formatter: function () {
if(fiscal13){
var perDate = new Date(this.value);
return 'Per' + (perDate.getMonth() + 1);
}
}
}
}
I am not sure if I am right, but I think you are overdoing this.
Let's keep original data, so remove fiscal13Data.Data.forEach(function(item) { .. }); function. And When creating data, use simply index of the point as x-value:
var cost = [],
usage = [],
dataLength = fiscal13Data.Data.length
i = 0;
for (i; i < dataLength; i += 1) {
// need to sum costs
cost.push([
i, // the index
fiscal13Data.Data[i]['Cost'] // cost
]);
usage.push([
i, // the index
fiscal13Data.Data[i]['Usage'] // Usage
]);
}
Now you can get to the "Per13/2016" strings in a simple way in xAxis labels' formatters:
var str = fiscal13Data.Data[this.value].Date;
In tooltip formatter, it is almost exactly the same:
var str = fiscal13Data.Data[this.x].Date;
And here is working demo: http://jsfiddle.net/qneuh4Ld/3/
Note: You data looks a bit strange - don't you want to sort it first? Also, you have twice every date (e.g. "Per13/2016" - once for "water" and once for "electric").
I am using ShinobiCharts in my iOS app to plot a line chart. This requires a feature where in the default view will be in Days. When i pinch zoom, i will be getting Weeks data, and more pinch zooming will give me Months data. Same applies for zoom out in reverse order.
I am not able to find a way to show this data at different zoom levels.
Please help me with this.
Im using following delegate method to check zoom level
- (void)sChartIsZooming:(ShinobiChart *)chart withChartMovementInformation:
(const SChartMovementInformation *)information;
but i dont find any way to check zoom levels.
One way of checking this is to determine the number of days currently displayed within the axis' visible range.
First off you'll need a way to record the current granularity of data on display in the chart:
typedef NS_ENUM(NSUInteger, DataView)
{
DataViewDaily,
DataViewWeekly,
DataViewMonthly,
};
The initial view will be DataViewDaily and is assigned within viewDidLoad to the property currentDataView.
Then within sChartIsZooming:withChartMovementInformation: you could do:
- (void)sChartIsZooming:(ShinobiChart *)chart withChartMovementInformation:(const SChartMovementInformation *)information
{
// Assuming x is our independent axis
CGFloat span = [_chart.xAxis.axisRange.span doubleValue];
static NSUInteger dayInterval = 60 * 60 * 24;
NSUInteger numberOfDaysDisplayed = span / dayInterval;
DataView previousDataView = _currentDataView;
if (numberOfDaysDisplayed <= 7)
{
// Show daily data
_currentDataView = DataViewDaily;
}
else if (numberOfDaysDisplayed <= 30)
{
// Show weekly data
_currentDataView = DataViewWeekly;
}
else
{
// Show monthly data
_currentDataView = DataViewMonthly;
}
// Only reload if the granularity has changed
if (previousDataView != _currentDataView)
{
// Reload and redraw chart to show new data
[_chart reloadData];
[_chart redrawChart];
}
}
Now within your datasource method sChart:dataPointAtIndex:forSeriesAtIndex: you can return the appropriate data points by switching on the value of _currentDataView.
Note that you may need to also update sChart:numberOfDataPointsForSeriesAtIndex to return the number of points to display at the current view level.